Polishing head for the zonal machining of optical spectacle surfaces

ABSTRACT

A polishing head for spectacle surfaces with a basic body for attachment to a polishing spindle, with an elastic supporting part for a polishing film which is or can be attached, wherein the supporting part comprises a recess with a wall surface and a depth t, and the polishing film comprises at least one hole, wherein the hole forms an access to the recess, wherein the polishing film comprises in addition to the hole at least one further hole, which is arranged in the area of an edge of the recess and is at a radial distance a from the hole, wherein the further hole forms an outlet channel for polishing agent from out of the recess or the wall surface is raised at least over one section of the depth t, and/or with reference to a circumference, at least in segments in relation to the rotational axis D at an angle α, and/or the supporting part comprises at least one groove which is provided in the front side with a groove base and a depth t 1 , which is connected to the recess and/or the supporting part comprises at least one channel with an opening which connects the recess and the front side. A method in which a reserve supply of polishing agent is filled into the recess in the supporting part prior to the conjoining of the polishing head and the surface to be polished.

FIELD OF THE INVENTION

The invention relates to a polishing head for the zonal machining of optical spectacle surfaces with a basic body which comprises a rotational axis D for attachment to a polishing spindle, with an elastic supporting part which is arranged on the basic body, on which a polishing film is arranged, wherein the supporting part comprises a recess of the depth t and the polishing film comprises at least one hole, wherein the hole forms an access to the recess.

Furthermore, the invention relates to a polishing head for the zonal machining of optical spectacle surfaces with a basic body which comprises a rotational axis D for attachment to a polishing spindle and with an elastic supporting part which is arranged on the basic body which comprises a front side for attaching a polishing film, wherein the supporting part comprises a central recess with a depth t and with a wall surface.

The invention also relates to a method for polishing optical spectacle surfaces with a zonal polishing tool, consisting of a polishing spindle and a polishing head arranged thereon, which is formed by a basic body for attachment to the polishing spindle and an elastic supporting part which is arranged on the basic body with a recess, and a polishing film which is attached to the supporting part.

BACKGROUND OF THE INVENTION

A polishing plate for a tool for the fine machining of optical surfaces on spectacle lenses is already known from DE 10 2005 010 583 A1. This polishing plate comprises a supporting body to which a foam layer is attached, on which a polishing film rests. The polishing film is equipped in a central area with at least one opening. The opening ensures during machining that pressure is compensated and provides fluid polishing agent from inside the foam layer, as a result of which improved rinsing and cooling of otherwise neglected polishing plate areas is achieved.

The recess within the supporting part known from DE 10 2005 010 583 A1 is designed to serve as a reservoir for fluid polishing agent during machining which has been stored or absorbed in the foam, i.e. in the supporting part itself, and which when the supporting part is tumbled or compressed enters the recess starting from the pores. From there, it is to be fed to the polishing process via the opening in the polishing film. A separate filling of the recess according to the invention prior to attachment of the tool is not provided according to the principle of the prior art. To a far greater extent, it is common that the surface to be polished on the one hand, and the polishing head on the other, is provided after attachment onto the surface to be polished with polishing agent from the side, which is then to be fed inwards due to the capillary function of the supporting part.

The opening in the polishing film accordingly serves to transport onward fluid polishing agent from the inside of the foam layer. The foam layer itself comprises a recess in the area of the opening in the polishing film which serves during machining as a reservoir for the fluid polishing agent.

U.S. Pat. No. 3,128,580 describes a grinding and polishing machine with a grinding an polishing head which comprises several grooves which serve to more effectively transport cooling agent to the workpiece surface which is to be machined. Here, the grooves are provided within the grinding and polishing coating, wherein the respective groove is assigned a groove-shaped recess within the basic body of the grinding and polishing head. Furthermore, within the grinding and polishing coating, a centric, circular recess is provided which is assigned a corresponding, pot-shaped recess within the basic body for retaining cooling agent. According to the exemplary embodiment in FIG. 11, the grooves or associated groove-shaped recesses run through into the area of the centric recess or opening, wherein a space is provided between the groove and the centric recess. As can clearly be seen in FIGS. 10 and 12, there is however no through-flow connection between the centric recess and the respective groove or groove-shaped recess. According to the exemplary embodiments in FIGS. 4, 8 and 9, there is a through-flow connection between the centric recess and the groove or groove-shaped recess, but there is no space between the groove-shaped recess and the centric recess.

The different recesses serve as a retaining reservoir for cooling agent which is probably designed to exit the recesses upwards towards the workpiece in stages during the process. No direct onward transportation between the different recesses is described.

SUMMARY OF THE INVENTION

The object of the invention is to design and arrange a polishing film or polishing head for optical spectacle surfaces in such a manner that improved transportation of polishing agent between the polishing film and the surface to be machined is guaranteed.

The object is attained according to the invention by means of the objects or method according to the claims.

The fact that the polishing film comprises in addition to the hole at least one further or separate hole which is arranged in the area of an edge of the recess and which is at a radial distance a from the hole, results in an outlet for polishing agent from out of the recess. The additional or separate hole can also be formed as a groove-shaped extension of the central hole. The aforementioned distance relates in this case to the respective radial outside edge of the central hole on the one hand and the groove-shaped extension on the other. Due to the centrifugal forces which are created with the rotation, the polishing agent is forced outwards or upwards in the edge area of the recess, regardless of the form of the polishing agent. Due to the additional hole or groove-shaped extension according to the invention in the edge area of the recess, in the direction of which the polishing agent is forced upwards or outwards due to the centrifugal forces, the polishing agent can exit from the hole and thus be incorporated or distributed between the polishing film and the surface to be machined. The hole or groove-shaped extension is here designed in terms of its size or diameter in accordance with the required volume flow. This also applies to the number of holes or groove-shaped extensions which are arranged over the circumference. When polishing optical spectacle surfaces or aspherical surfaces, it should be assumed that the polishing film rises up from the polishing surface during the polishing process, as a result of which the additional hole according to the invention is not continuously closed by the surface to be machined. Accordingly, the separate hole according to the invention is significantly smaller in design than the centric opening already known from the prior art, taking into account the torques to be achieved during the polishing process, i.e. taking into account the anticipated volume flow on the one hand and the viscosity of the polishing agent on the other. The diameter of the hole according to the invention is between 0.2 and 4 mm.

The wall surface which is raised at least over one part of the depth t and/or in relation to a circumference at least in segments in relation to the rotational axis D at an angle α without a re-entrant angle, guarantees improved transportation of polishing agent in the radial and axial direction from out of the recess by using the centrifugal forces which are created during machining. This feature can be provided as an alternative or as a supplement to the transportation of the polishing agent flow.

Here, it is provided that the recess opens towards a side facing the polishing surface, due to the raising of the wall surface, as is shown in the exemplary embodiments in FIGS. 2, 4, 5 a, 5 b, 5 c, 6 a and 8, so that greater quantities of polishing agent are transported to the edge of the recess.

The polishing film to be arranged usually comprises a centric hole, wherein the hole forms an access to the recess for the purpose of filling. With the raising of the wall surface, an increased share of force is applied onto the polishing agent which rotates with the polishing plate in the axial direction to the rotational axis, so that said agent is significantly more effectively transported out of the recess, if necessary upwards via a channel to a polishing film or outlets which is or are to be provided there.

The groove which is provided in the free front side of the supporting part and which leads to the recess in the flow connection, with a groove base and a depth t1, guarantees an increased polishing agent flow from out of the recess at a height below the polishing film. This feature can be provided as an alternative or supplement to the transportation of the polishing agent flow. The polishing agent can thus exit from out of the recess via the groove below the polishing film to be applied in the radial direction of the groove, and be transported onward by means of the groove.

The depth t1 of the groove is smaller than the depth t of the recess. The groove thus forms a channel in the supporting part which is open to one side, which is at least partially closed by the polishing film with the exception of an outlet opening or an exit. If the depth t1 of the groove is the same as the depth t of the recess, the recess is segmented, as is described below. This also applies when the depth t of the recess or the depth t1 of the groove varies over the radius.

Alternatively or as a supplement, the supporting part can comprise at least one channel with an opening which connects the recess and the front side, wherein the opening of the channel is provided in a depth t2 of the recess or close to the floor in relation to a central axis M of the channel. The polishing agent can exit from out of the recess close to the floor via the channel. The channel thus represents a closed variant of a groove, the depth t1 of the groove base of which varies with the radius.

As an alternative to the case described in the introduction, it can be provided that the recess, due to a reverse raising of the wall surface in the opposite direction, thus opens towards the basic body, and accordingly is not formed without a re-entrant angle. In this case, the polishing agent, due to the centrifugal forces, is transported in greater quantities into an opening of a channel close to the floor, or into the channel which connects the recess or area of the recess which is close to the floor with a front side of the supporting part.

When a polishing head of the type described above is used, with which for the purpose of usage on the supporting part, a polishing film can be attached with at least one hole, wherein the hole forms an access to the recess, it can be advantageous when the polishing film comprises an inner side which faces or can be faced towards a supporting part, and an outer side which can be placed onto the optical surface, and when the polishing film comprises, in addition to the hole, at least one further hole which is arranged at a radial distance a to the hole, which is arranged in the area of an edge of the recess and/or in the area of the groove and/or in the area of an opening of the channel, wherein the further hole forms an outflow channel for polishing agent from out of the recess, from out of the groove and/or from out of the opening. As a result, the advantages described above relating to the transportation of polishing agent to the surface to be machined are achieved.

If the central axis M of the channel comprises an angle β of between 25° and 60° with the rotational axis D, the polishing agent is transported in an optimum manner outwards and upwards due to the centrifugal forces which are created during machining. The position ultimately depends on the required outlet site on the front side, or out of the polishing film which rests on it, and on the diameter of the supporting part. Preferably, the channel opens out in the recess close to the floor.

The channel can also be curved or parabolic, so that the angle β varies over the length of the channel or over the radius of the polishing head. The channel can be flatter close to the rotational axis, which despite lower centrifugal forces facilitates the transportation of the polishing agent. With a greater distance from the rotational axis D, the channel can be steeper, which initially impairs the transportation of the polishing agent. Due to the centrifugal forces which increase with the radius, this disadvantage is compensated, however.

It can also be advantageous when the polishing film comprises an inner side which faces or can face the supporting part, and an outer side which can be placed on the optical surface, wherein the polishing film also comprises, in addition to the hole, at least one groove with a groove base which is provided on the inner side, and at least one recess on the outer side which partially opens the groove base in the direction of the outer side, and which comprises a distance d from the hole. The groove here preferably runs in the radial direction. It connects an inflow for polishing agent, preferably the edge area of the recess with the recess which lies further outwards in the radial direction, so that polishing agent is guided, starting from the recess in the supporting part, through the groove to the recess and thus between the polishing film and a surface to be polished. The open side of the groove is closed when the polishing film is placed onto the supporting part, and is thus formed as a channel. The groove in the polishing film can here be stamped and/or produced as part of the forming process of the polishing film. It is also feasible for the groove to be formed after the forming process of the polishing film using a cutting machining process. These features can be provided as an alternative or supplement to the facilitation of the polishing agent flow.

Here, it can be advantageous when the groove in the supporting part, the groove in the polishing film and/or the channel in the supporting part runs in the radial direction to the rotational axis D. The length or radial extension of the groove or of the channel also depends on how far the recess according to the invention or the hole according to the invention on the outer side of the polishing film is removed from the central hole provided in the polishing film.

As an alternative or supplement, it is advantageous when the central hole of the polishing film forms an access to the recess and the groove of the polishing film, the groove of the supporting part and/or the channel for the supporting part forms an outflow channel for polishing agent from out of the recess, wherein the polishing film comprises a hole which for the purpose of the exit of polishing agent connects to the groove of the supporting part and/or the channel of the supporting part. As has already been described, the supporting part of the polishing head in connection with the polishing film described above forms an outflow channel for polishing agent stored in the recess of the supporting part, which is arranged below the polishing film. By means of the groove, the polishing agent is guided radially outwards over any distance required through to the outlet hole, starting from the recess or an edge of the recess and due to the displacement effect created with the rotation, in order to exit outwards there. The size or dimension of the groove or channel and the size of the connecting hole in the polishing film is also selected according to the required polishing agent flow, depending on the polishing agent pressure, which varies according to the viscosity of the polishing agent and the torque.

It can be of particular significance to the present invention when the hole in the polishing film comprises a diameter d1 and the recess on the edge comprises a diameter d2, wherein the diameter d1 is smaller than the diameter d2 and the polishing film protrudes over the edge of the recess, and the recess at least partially closes in the edge area in the axial direction. Thus, the edge area of the recess in which the polishing agent would exit upwards and/or to the side due to the centrifugal forces, is closed by the polishing film. The polishing film can accordingly not exit there, or only into the holes and/or grooves which are provided as described above, which serve a defined onward transportation and elimination of polishing agent towards the outer surface. The protrusion which is thus formed is between 15% and 90%, preferably between 20% and 60% of the half diameter d2.

In connection with the design and arrangement according to the invention, it can be advantageous when the polishing film comprises a first function area F1 and corresponding means which guarantees a lid function in partial areas of the edge of the recess due to a protrusion and an onward transportation function for polishing agent radially outwards from out of the recess through the groove and/or in the axial direction through the additional hole. Due to the groove, an onward transportation function for the polishing agent is also guaranteed which acts in the axial direction. However, the radial onward transportation function is of primary significance due to the length of the groove. The lid function guarantees the retention of polishing agent, so that the restricted volume of polishing agent can be defined within the scope of the onward transportation function, and thus transported onwards in doses, and ultimately relinquished to the required areas of the polishing agent foil. The onward transportation function is guaranteed on the side of the supporting part by the groove or channel in the supporting part.

It can furthermore be advantageous when the polishing film comprises a second function area F2 and corresponding means which guarantees the outlet function for polishing agent towards the outer side through the additional hole on the edge of the recess, through the hole which leads to the groove or channel in the supporting part and/or through the recess which leads to the groove in the polishing film. The second function area guarantees the required outflow of polishing agent to the positions which can be freely selected on the outer side of the polishing film.

It can also be advantageous when the polishing film comprises a lower section with the inner side and an upper section with the outer side, wherein the first function area F1 is assigned to the lower section, and the second function area F2 is assigned to the upper section. The polishing film can here be single, dual or triple-layered for the purpose of creating an onward transportation system according to requirements.

For this purpose, it can alternatively also be advantageous when the lower section and the upper section are formed as a single piece and/or are of the same material, or when the lower section and the upper section form separate components. If two different components are present, the lower section can also be assigned a stiffening function, so that the adaptability of the polishing film in connection with the flexible support is restricted in the downwards direction, i.e. towards smaller radii.

Here, it can be advantageous when the recess comprises a volume which is at least 0.3 ml or 0.4 ml or 0.5 ml or 0.6 ml. The main function of the supporting part continues to be to support the polishing film when the surface is being polished. The support function is reduced overall or is eliminated completely in the area of the recess according to the size of the centric recess which is designed as a polishing agent reserve supply, so that the radial extension of the recess must ultimately also be restricted. Taking into account the height of the supporting part, i.e. the depth of the recess, a required storage volume for polishing agent, albeit one which is restricted in terms of its upper level, can thus be achieved.

Ultimately, it can be advantageous when the recess is formed as a funnel and/or cup and/or truncated cone, wherein the raised part of the wall surface of the recess is level or flat. Flat or level wall surfaces can be produced somewhat more easily due to the tools available. The funnel and/or cup-shaped design of at least the upper section of the recess improves the polishing agent pressure in the upper edge area of the recess which is created with the rotation, as is mentioned above.

For this purpose, it can be advantageous when the raised part of the wall surface of the recess comprises a straight or parabolic limitation line B which comprises an angle α with the rotational axis. With the parabolic limitation line B, the angle α varies in relation to the depth t. With the varying angle α, the distance between the surface of the rotational axis when selecting the angle α can be taken into account, i.e. with surface areas at a lower distance from the rotational centre or to the rotational axis D, the angle α is correspondingly wide, and with surfaces at a greater distance from the rotational centre, it is correspondingly smaller, as is shown in the example in FIG. 5 c. Thus, excess outflow or polishing agent pressure in the areas at a greater distance from the rotational centre is avoided, while at the same time, the depth t of the recess is bridged.

Ultimately, it can be advantageous when the recess or at least the funnel and/or cup-shaped part of the recess is segmented in relation to the circumferential direction U into several partial segments. The lack of support by the supporting part which results from the recess is at least partially rectified with a segmented structure of the funnel-shaped parts of the recess. On the one hand, this guarantees a somewhat higher volume for the polishing fluid, while on the other, guaranteeing a support function which is dependent on the size of the segments or the extensions of the recess.

Finally, it can be advantageous when the basic body comprises a central polishing agent channel. The polishing head can be supplied with polishing agent via the polishing agent channel, which is provided or fed via the polishing spindle. The polishing agent can be transported via the polishing agent channel into the recess and transported from there in the manner described above.

Due to the fact that in terms of the method, a reserve supply of polishing agent is filled into the recess in the supporting part prior to conjoining the polishing head and the surface to be polished, a significantly greater reserve supply of polishing agent results, which during the subsequent machining is transported using the means described above between the polishing film and the surface to be processed. The same applies accordingly when polishing agent is fed via the polishing agent channel. Since the quantities which can be fed via the polishing agent channel are significantly greater, good cooling effects can also be achieved alongside reproducible results.

For the method, it is advantageous when the filling procedure is repeated during the polishing process of one spectacle surface several time, if necessary, between two and ten times. The overall volume of polishing agent which is available in general for one polishing process can be increased by the appropriate factor, on the basis of the aforementioned volumes of the recess, which improves the quality of the polishing process and above all, however, the reproducibility of the polishing process.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and details of the invention are explained in the patent claims and in the description and are illustrated in the figures, in which:

FIG. 1 shows a perspective view of the polishing head with a polishing film;

FIG. 2 shows a cross-section view from FIG. 1;

FIG. 3 shows a top view of the polishing head as a schematic diagram;

FIG. 4 shows a cross-section view according to section A-A of FIG. 3;

FIGS. 5 a-5 d show different exemplary embodiments for the flexing surface of the sheath surface of the recess;

FIG. 6 shows a schematic diagram as a top view with a segmented recess;

FIG. 6 a shows a section B-B from FIG. 6;

FIG. 7 shows a top view with slit-shaped extensions of the recess;

FIG. 7 a shows a section C-C from FIG. 7;

FIG. 7 b shows a cross-section view of alternative embodiments;

FIG. 8 shows a cross-section view of the perspective view; and

FIG. 9 shows a cross-section view of a further embodiment.

DETAILED DESCRIPTION OF THE INVENTION

A polishing head 1 according to FIG. 1 comprises a basic body 2 which is formed of synthetic material with a supporting part 3 which is formed on it made of foam and a polishing foam 4 which is arranged on the supporting part 3. The basic body 2 serves to retain a polishing spindle 7 which is not shown further, and comprises for the purpose of machine handling a collar 2.1 and catch springs 2.2 for clipping onto the spindle, not shown, or onto a spindle head.

The polishing film 4 comprises on its upper side a hole 4.1 which is arranged coaxially to a rotational axis D. Additionally, further holes 4.4 to 4.4′″ are provided at a radial distance. Furthermore, four recesses 4.7 to 4.7′″ are provided on the upper side, which are not, however, a through-hole.

It can be seen in FIG. 2 that both the centric hole 4.1 and the further holes 4.4 to 4.4′″ which are positioned further outwards are formed as a whole, i.e. they extend through the entire film.

The polishing film 4 is formed from the two layers 4 a, 4 b. The aforementioned holes 4.1-4.4 here pass through both layers 41, 4 b. Furthermore, the lower layer 4 b comprises a recess or groove 4.5, starting from the respective hole 4.4, which extends through into the area of the respective recess 4.7.

The supporting part 3 comprises a centrically arranged recess 3.1 which extends down to the supporting part 3, starting from the upper side. The recess 3.1 comprises a cone-shaped sheath surface 3.2, which comprises an angle α with the rotational axis D. The recess 3.1 serves as a polishing agent reserve supply which is inserted into the recess 3.1 prior to the polishing process. The respective hole 4.4 to 4.4′″ or the start of the respective groove 4.5 is here provided in the area of an edge 3.3 of the recess 3.1. Were the polishing head 1 to be rotated, the polishing agent located in the recess 3.1 would be transported outwards, and consequently upwards, and enters the hole 4.4 or exits upwards from the hole 4.4 in the area of the edge 3.3. On the other hand, the polishing agent is transported to the recess 4.7 through the groove 4.5 or the channel which is formed together with the groove 4.5 and the supporting part 3 and also exits through the recess 4.7.

According to the illustration in FIG. 3, the respective groove 4.5 extends in the radial direction to the recess 4.7, starting from the hole 4.4.

As can be seen in FIG. 2, the polishing film protrudes over the edge 3.3 of the recess 3.1 by an overhang 4.8. The overhang 4.8 is approximately 40% of the half diameter d2 of the recess 3.1. Accordingly, the polishing agent which is forced upwards or outwards by the rotation can only exit upwards or radially outwards through the hole 4.4 or the groove 4.5.

The groove 4.5 comprises a length 1, wherein the hole 4.4 comprises a distance a from the centric hole 4.1, as a result of which the overhang 4.8 would at least partially be accounted for. The recess 4.7 is accordingly distanced from the hole 4.4 by the length 1 of the groove 4.5, and is at a corresponding distance d from the hole 4.1.

Opposite the further hole 4.4, another embodiment of the further hole 4.4 a is shown. The further hole 4.4 a is groove-shaped and is connected to the central hole 4.1. The distance a in this case relates to the limitation line of the respective hole 4.1, 4.4 a which lies radially outside. The size of the respective hole 4.1, 4.4 a, as well as the width and length and the number of further holes 4.4, 4.4 a which are distributed around the circumference can differ depending on the type of application.

According to the cross-section view A-A from FIG. 3, the recess 3.1 comprises in the area of the edge 3.3 a diameter d2, and tapers downwards by approximately 70% to a diameter d3.

According to the illustration in FIG. 4, the polishing head 1 thus formed can be placed against a surface 8.1 of a workpiece 8 or a lens 8.

Each of the two layers 4 a, 4 b of the polishing head 4 are assigned a separate function area F1, F2. The lower layer 4 b guarantees on the one hand the lid function by means of the overhang 4.8 over the edge 3.3 of the recess 3.1. Furthermore, the lower layer 4 b fulfils the outlet and onward transportation function of the polishing agent into the hole 4.4 or into the groove 4.5 towards the recess 4.7. The upper layer 4 a is essentially assigned the outlet function, since there, the polishing agent exits from the hole 4.4 or from the recess 4.7 at a required site and can be incorporated between the polishing film 4 and the surface 8.1 to be machined, and there fulfils the polishing function or effectively supports it.

The recess 3.1 can comprise different forms with regard to its wall surface 3.2 according to exemplary embodiments 5 a to 5 d. A limitation line B of the projection of the wall surface 3.2 which results according to the cross-section view can be funnel shaped according to FIG. 5 a, bow-shaped or parabolic according to the exemplary embodiments in FIGS. 5 b and 5 c and/or cylindrical according to FIG. 5 d. In the first three cases, the positioning angle α of the wall surface 3.2 varies depending on a height or depth t of the recess 3.1. This can be advantageous, in particular in the case shown in FIG. 5 c, since in the areas close to the rotational axis D in the base of the recess, the centrifugal forces which ac in the radial direction will be smaller than in the areas which are at a greater distance from the rotational axis, i.e. in the area of the edge 3.3.

Even with a cylindrical recess according to FIG. 5 d, a raising of the filling level of the polishing fluid on the edge 3.3 of the recess 3.1 is achieved, so that the polishing fluid can also exit through the hole 4.4 or the groove 4.5. The height of the section of the wall surface 3.2 which is raised in relation to the rotational axis D can, as in the exemplary embodiment shown in FIG. 5 a, be greater than the overall depth t of the recess 3.1.

According to the exemplary embodiment in FIG. 6 and the associated cross-section view B-B in FIG. 6 a, it is provided that the recess 3.1 is segmented in the circumferential direction U at least partially, i.e. the recess 3.1 is supplemented by three wing-shaped extensions 3.1 a, 3.1 b, 3.1 c. Within the wing-shaped extensions 3.1 a, 3.1 b, 3.1 c, the wall surface 3.2 is raised in relation to the rotational axis D. The central section of the recess 3.1 is, insofar as it is limited, cylindrical. The wing-shaped extensions 3.1 a, 3.1 b, 3.1 c are also three further segments of the recess 3.1 alongside the central section of the recess 3.1. Depending on the length and width of the extensions 3.1 a-3.1 c, the support function of the supporting part is impaired.

In the exemplary embodiment shown in FIG. 7, the recess 3.1 is segmented in a similar manner to the exemplary embodiment shown in FIG. 6, wherein the segmentation is formed by three slit-shaped extensions 3.1 a, 3.1 b, 3.1 c in the top view which run in the radial direction. In addition to the central recess 3.1 and the three slit-shaped extensions 3.1 a to 3.1 c, an opening 3.7 b of a channel 3.7 which is shown in FIG. 7 a is shown on the upper side or front side 3.4 of the supporting part 3.

According to the cross-section view C-C in FIG. 7 a, on the left-hand side, the slit-shaped extensions 3.1 a to 3.1 c have the same depth t as the recess 3.1 itself. The slit-shaped recesses 3.1 a to 3.1 c are according to the exemplary embodiment in FIG. 7 rectangular with reference to the top view. However, these can also comprise the ovular, long holes, square or triangular form of a star point.

According to the exemplary embodiment shown in FIG. 7 a, on the right-hand side, a channel 3.7 is provided in the supporting part 3 which, beginning in the central recess 3.1, runs radially outwards and upwards towards the free front side 3.4. The channel 3.7 comprises a central axis M which with the rotational axis D comprises an angle β of approximately 55°.

The channel 3.7 forms an opening 3.7 a in the wall surface 3.2 of the recess 3.1, which in relation to the central axis M is placed at a depth t2, measured from the front side 3.4. The channel 3.7 opens out into an opening 3.7 b on the front side 3.4. The opening 3.7 b is at a radial distance from the central recess 3.1, as is shown in FIG. 7.

According to the exemplary embodiment shown in FIG. 7 b, on the left-hand side, the groove 3.5, can be flatter or less deep than the central recess 3.1. The groove 3.5 or the groove base 3.6 here has the depth t1 which totals approximately 40 percent of the depth t of the central recess 3.1.

According to the exemplary embodiment shown in FIG. 7 b, on the right-hand side, the channel 3.7 can be curved or parabolic, in a similar manner to the recess according to FIG. 5 b or 5 c. The positioning angle β between the central channel axis M and the rotational axis D thus varies with the radius.

In general, it is also possible for the groove base 3.6 to be curved or parabolic according to the exemplary embodiment shown in FIG. 7 b on the left-hand side, in a similar manner to the channel 3.7 according to the exemplary embodiment shown in FIG. 7 b on the right-hand side. As soon as the depth t1 in the area of the central recess 3.1 reaches the depth t of the central recess 3.1, when the groove base 3.6 is curved or parabolic, an embodiment results which is similar to FIG. 6 or FIG. 6 a, according to which a segmented recess 3.1 with the wing-shaped extensions 3.1 a to 3.1 c according to the top view is provided. In contrast to the exemplary embodiment shown in FIG. 6, the extensions 3.1 a to 3.1 c are significantly longer and narrower, and are to this extent more slit-shaped, than in the exemplary embodiment shown in FIG. 6.

In the cross-section view shown in FIG. 8, the respective groove 3.5, 3.5″ is provided in the supporting part. The groove 3.5 extends in the radial direction, starting from the recess 3.1 or its upper edge 3.3, through to the height of the respective hole 4.7, 4.7″ in the polishing film 4. The polishing agent located in the recess 3.1 is transported out of the cone-shaped recess when a rotation occurs, and through to the hole 4.7 of the polishing film 4 via the groove 3.5, and finally exits from the hole 4.7. At the latest when the groove 3.5 is filled with polishing agent, polishing agent exits the hole 4.4 which is arranged in front of the hole in relation to the radial direction.

According to FIG. 8 on the left-hand side, the hole 4.4 or 4.4″ is not provided. Only the hole 4.7″ at the end of the groove 3.5″ is provided from which the polishing agent can exit outwards.

The basic body 2 comprises a polishing agent channel 2.3 which is designed as a hole, and which is arranged coaxially to the rotational axis D. Via the polishing agent channel 2.3, the polishing head 1 or the recess 3.1 is supplied with polishing agent as an alternative or a supplement, which is provided by means of a polishing spindle 7 shown as a sketch in FIG. 4.

According to the exemplary embodiment shown in FIG. 9, the recess 3.1 opens downwards to the base part 2 not shown (see FIG. 8). The polishing agent is transported via the respective channel 3.7, 3.7″ to the front side 3.4 of the supporting part. The form of the recess 3.1 which extends downwards guarantees the transportation of the polishing agent from the recess 3.1 into the respective channel 3.7, 3.7″ or its respective opening 3.7 a, 3.7 a″.

LIST OF REFERENCE NUMERALS

-   1 Polishing head -   2 Basic body -   2.1 Flange, collar -   2.2 Catch spring -   2.3 Polishing agent channel, hole -   3 Supporting part -   3.1 Recess, mould -   3.1 a Extension, propeller-shaped, slit-shaped, partial segment -   3.1 b Extension, propeller-shaped, slit-shaped, partial segment -   3.1 c Extension, propeller-shaped, slit-shaped, partial segment -   3.2 Wall surface, sheath surface -   3.3 Edge -   3.4 Front side, free -   3.5 Groove -   3.6 Groove base -   3.7 Channel -   3.7 a Opening, below -   3.7 b Opening, above, front side -   4 Polishing film -   4 a Upper part, layer -   4 b Lower part, layer -   4.1 Hole -   4.2 Inner side -   4.3 Outer side -   4.4 Hole -   4.4′ Hole -   4.4″ Hole -   4.4′″ Hole -   4.4 a Hole -   4.5 Groove -   4.6 Groove base -   4.7 Recess, hole -   4.7′ Recess -   4.7″ Recess -   4.7′″ Recess -   4.8 Overhang -   7 Polishing spindle -   8 Lens, workpiece -   8.1 Optical spectacle surfaces, aspherical surface -   α Angle -   β Angle -   a Distance -   b Distance -   B Limitation line -   D Rotational axis -   d Distance -   d1 Diameter -   d2 Diameter -   d3 Diameter -   F1 Function area -   F2 Function area -   l Length -   M Central axis channel 3.7 -   t Depth -   t1 Depth -   t2 Depth -   U Circumferential direction 

1. A polishing head for the zonal machining of optical spectacle surfaces, comprising: a basic body which comprises a rotational axis D for attachment to a polishing spindle, with an elastic supporting part which is arranged on the basic body, on which a polishing film is arranged, wherein the supporting part comprises a recess of a depth t and the polishing film comprises at least one hole, wherein the hole forms an access to the recess, wherein the polishing film comprises, in addition to the hole, at least one further hole which is arranged in an area of an edge of the recess, and which is at a radial distance a from the hole, wherein the further hole forms an outlet channel for polishing agent from out of the recess.
 2. A polishing head for the zonal machining of optical spectacle surfaces, comprising: a basic body which comprises a rotational axis D for attachment to a polishing spindle and with an elastic supporting part which is arranged on the basic body, which comprises a front side for attaching a polishing film, wherein the supporting part has a recess which comprises a wall surface with a depth t, wherein the wall surface is raised at least over a part of a depth t and/or in relation to a circumference at least in segments in relation to the rotational axis D at an angle α, wherein the wall surface is designed without a re-entrant angle and/or the supporting part comprises at least one groove which is provided in the front side with a groove base and a depth t1, which connects to the recess, wherein the depth t1 is less than the depth t, and/or the supporting part comprises at least one channel which connects the recess and the front side with an opening, wherein the opening of the channel is provided at a depth t2 of the recess with reference to a central axis M of the channel.
 3. The polishing head according to claim 2, with a polishing film which is attached to the supporting part, or a polishing film wherein the polishing film comprises at least one hole, wherein the hole forms an access to the recess and the polishing film comprises an inner side which faces or can face the supporting part and an outer side which can be placed on the optical surface, and that the polishing film also comprises, in addition to the hole, at least one further hole with a radial distance a from the hole, which is arranged in the area of an edge of the recess and/or in the area of the groove and/or in the area of an opening of the channel, wherein the further hole forms an outflow channel for polishing agent from out of the recess, the groove and/or the opening.
 4. The polishing head according to claim 2, wherein the central axis M of the channel comprises with the rotational axis D an angle β between 25° and 60°.
 5. The polishing head according to claim 2, wherein the channel is curved or parabolic, wherein the angle β varies over the length of the channel.
 6. The polishing head according to claim 1, wherein the polishing film comprises an inner side which faces or can face the supporting part and an outer side which can be placed on the optical surface, wherein the polishing film comprises in addition to the hole at least one groove which is provided on the inner side with a groove base, and comprises on the outer side at least one recess which partially opens the groove base towards the outer side and which is at a distance d from the hole, wherein the groove with the recess forms an outflow channel for polishing agent from out of the recess.
 7. The polishing head according to claim 1, wherein the polishing film comprises a first function area F1 and corresponding means for a) a lid function in partial areas of the edge of the recess by means of an overhang b) an onward transportation function for polishing agent from out of the recess radially outwards through the groove and/or in the axial direction through the further hole.
 8. The polishing head according to claim 1, wherein the polishing film comprises a second function area F2 and corresponding means for the outlet function for polishing agent towards the outer side through the further hole and/or through the recess.
 9. The polishing head according to claim 7, wherein the polishing film comprises a lower section with the inner side and an upper section with the outer side, wherein the first function area F1 is assigned to the lower section and the second function area F2 is assigned to the upper section.
 10. The polishing head according to claim 1 wherein the recess comprises a volume which is at least 0.3 ml.
 11. The polishing head according to claim 1, wherein the recess is funnel and/or cup-shaped, wherein the wall surface of the recess comprises a straight or parabolic limitation line B with reference to the cross-section view.
 12. The polishing head according to claim 1, wherein the recess or at least the funnel and/or cup-shaped part of the recess is segmented into several partial segments with reference to the circumferential direction U.
 13. The polishing head according to claim 1, wherein the basic body comprises a central polishing means channel.
 14. A method for polishing optical spectacle surfaces with a zonal polishing tool, consisting of a polishing spindle and a polishing head arranged on it, which is formed from a basic body for attachment to the polishing spindle and an elastic supporting part which is arranged on the basic body with a recess and a polishing film which is attached to the supporting part, comprising the steps of: filling prior to conjoining the polishing head and the surface to be polished, a reserve supply of polishing agent into the recess in the supporting part, and/or feeding polishing agent via the polishing agent channel.
 15. A method according to claim 14, wherein this filling procedure is repeated at least once during the polishing process of the one spectacle surface.
 16. The polishing head according to claim 10, wherein the recess comprises a volume which is at least 0.6 ml.
 17. The polishing head according to claim 3, wherein the polishing film comprises an inner side which faces or can face the supporting part and an outer side which can be placed on the optical surface, wherein the polishing film comprises in addition to the hole at least one groove which is provided on the inner side with a groove base, and comprises on the outer side at least one recess which partially opens the groove base towards the outer side and which is at a distance d from the hole, wherein the groove with the recess forms an outflow channel for polishing agent from out of the recess.
 18. The polishing head according to claim 17, wherein the polishing film comprises a first function area F1 and corresponding means for a) a lid function in partial areas of the edge of the recess by means of an overhang b) an onward transportation function for polishing agent from out of the recess radially outwards through the groove and/or in the axial direction through the further hole.
 19. The polishing head according to claim 18, wherein the polishing film comprises a second function area F2 and corresponding means for the outlet function for polishing agent towards the outer side through the further hole and/or through the recess.
 20. The polishing head according to claim 19, wherein the polishing film comprises a lower section with the inner side and an upper section with the outer side, wherein the first function area F1 is assigned to the lower section and the second function area F2 is assigned to the upper section. 